The present invention relates to apparatus for connecting fittings used in the conveyance of fluids, for example, irrigation systems, and particularly relates to male and female fittings having a threaded connection and a seal therebetween facilitating free angular orientation of the fittings to one another while maintaining the seal.
In many fluid flow systems, for example, underground irrigation systems, a large fluid supply pipe is provided with a service tee. The service tee is provided with a fitting which feeds a lateral line for flowing fluid to an exit port, e.g., a nozzle, or a sprinkler head. Typically, the male and female fittings between the service tee and the lateral line utilize a machined tapered pipe thread. Generally, the male fitting has threads which taper down to a smaller diameter at the distal end of the male fitting. The female threads likewise are tapered into general conformance with the male threads.
In tapered pipe threads of this type, the threads per se provide both sealing and structural connections between the fittings. However, these fittings are very difficult and costly to machine and require high precision to match the threads. Tapered threads of this type are also difficult and time-consuming to assemble in the field and require the use of lubricating and seal-enhancing tape and paste. Moreover, both functions of sealing and connecting the fittings to one another is difficult to achieve where the predetermined orientation of the pipes to which the fittings are connected is required. For example, if the lateral connection from the service tee is to extend at right angles to the service tee, i.e., normal to the direction of flow through the tee, the tapered threads must both seal and connect in order to locate the lateral connection in that orientation. If the threads are not properly oriented relative to one another, the fitting may require rotation beyond the orientation point to force the threads into the desired orientation. Conversely, threading short of the full threaded extent of the threads and leaving the threads loose to achieve the predetermined orientation may result in substantial leakage through the threaded joint. That is, in order to first achieve a seal and then orientation, very high torques may be required to rotate the fitting to the necessary orientation. It is possible that the additional rotation required may not be available due to this very high torque or the lack of remaining threads. Accordingly, there is a need for a connection system which affords connections between male and female fittings in a manner to provide the physical connection between the fittings, as well as the seal, without regard to the rotational orientation of the fittings.